Kraft Foods Inc is poised to launch a hostile bid for Cadbury Plc valuing the British confectionery business at around 11 billion pounds ($17.6 billion), a report in The Observer newspaper said.

In a separate interview with the Sunday Times, Kraft Chairman and Chief Executive Irene Rosenfeld said Cadbury CEO Todd Stitzer had failed to do the math quite accurately after he claimed Cadbury's own growth strategy would deliver superior returns compared with Kraft's cash and stock offer.

The Observer said Britain's Takeover Panel is preparing this week to set the U.S. group a deadline by which time it must put a firm offer on the table for Cadbury or walk away for six months.

Citing financial sources, the Observer said Kraft could bid 800 pence a share initially, rising to 850p ($1.36) as the battle reaches its climax during a 60-day time limit likely to be set by the Panel.

Kraft was not immediately available for comment.

(Reporting by Matt Scuffham; Editing by David Holmes)

($1=.6255 Pound)